drivers/extcon/extcon-adc-jack.c

   1 /*
   2  * drivers/extcon/extcon-adc-jack.c
   3  *
   4  * Analog Jack extcon driver with ADC-based detection capability.
   5  *
   6  * Copyright (C) 2012 Samsung Electronics
   7  * MyungJoo Ham <myungjoo.ham@samsung.com>
   8  *
   9  * Modified for calling to IIO to get adc by <anish.singh@samsung.com>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14  *
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/slab.h>
  19 #include <linux/device.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/err.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/workqueue.h>
  24 #include <linux/iio/consumer.h>
  25 #include <linux/extcon/extcon-adc-jack.h>
  26 #include <linux/extcon.h>
  27
  28 /**
  29  * struct adc_jack_data - internal data for adc_jack device driver
  30  * @edev:               extcon device.
  31  * @cable_names:        list of supported cables.
  32  * @num_cables:         size of cable_names.
  33  * @adc_conditions:     list of adc value conditions.
  34  * @num_conditions:     size of adc_conditions.
  35  * @irq:                irq number of attach/detach event (0 if not exist).
  36  * @handling_delay:     interrupt handler will schedule extcon event
  37  *                      handling at handling_delay jiffies.
  38  * @handler:            extcon event handler called by interrupt handler.
  39  * @chan:               iio channel being queried.
  40  */
  41 struct adc_jack_data {
  42         struct extcon_dev *edev;
  43
  44         const char **cable_names;
  45         int num_cables;
  46         struct adc_jack_cond *adc_conditions;
  47         int num_conditions;
  48
  49         int irq;
  50         unsigned long handling_delay; /* in jiffies */
  51         struct delayed_work handler;
  52
  53         struct iio_channel *chan;
  54 };
  55
  56 static void adc_jack_handler(struct work_struct *work)
  57 {
  58         struct adc_jack_data *data = container_of(to_delayed_work(work),
  59                         struct adc_jack_data,
  60                         handler);
  61         u32 state = 0;
  62         int ret, adc_val;
  63         int i;
  64
  65         ret = iio_read_channel_raw(data->chan, &adc_val);
  66         if (ret < 0) {
  67                 dev_err(&data->edev->dev, "read channel() error: %d\n", ret);
  68                 return;
  69         }
  70
  71         /* Get state from adc value with adc_conditions */
  72         for (i = 0; i < data->num_conditions; i++) {
  73                 struct adc_jack_cond *def = &data->adc_conditions[i];
  74                 if (!def->state)
  75                         break;
  76                 if (def->min_adc <= adc_val && def->max_adc >= adc_val) {
  77                         state = def->state;
  78                         break;
  79                 }
  80         }
  81         /* if no def has met, it means state = 0 (no cables attached) */
  82
  83         extcon_set_state(data->edev, state);
  84 }
  85
  86 static irqreturn_t adc_jack_irq_thread(int irq, void *_data)
  87 {
  88         struct adc_jack_data *data = _data;
  89
  90         queue_delayed_work(system_power_efficient_wq,
  91                            &data->handler, data->handling_delay);
  92         return IRQ_HANDLED;
  93 }
  94
  95 static int adc_jack_probe(struct platform_device *pdev)
  96 {
  97         struct adc_jack_data *data;
  98         struct adc_jack_pdata *pdata = dev_get_platdata(&pdev->dev);
  99         int i, err = 0;
 100
 101         data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
 102         if (!data)
 103                 return -ENOMEM;
 104
 105         if (!pdata->cable_names) {
 106                 dev_err(&pdev->dev, "error: cable_names not defined.\n");
 107                 return -EINVAL;
 108         }
 109
 110         data->edev = devm_extcon_dev_allocate(&pdev->dev, pdata->cable_names);
 111         if (IS_ERR(data->edev)) {
 112                 dev_err(&pdev->dev, "failed to allocate extcon device\n");
 113                 return -ENOMEM;
 114         }
 115         data->edev->name = pdata->name;
 116
 117         /* Check the length of array and set num_cables */
 118         for (i = 0; data->edev->supported_cable[i]; i++)
 119                 ;
 120         if (i == 0 || i > SUPPORTED_CABLE_MAX) {
 121                 dev_err(&pdev->dev, "error: pdata->cable_names size = %d\n",
 122                                 i - 1);
 123                 return -EINVAL;
 124         }
 125         data->num_cables = i;
 126
 127         if (!pdata->adc_conditions ||
 128                         !pdata->adc_conditions[0].state) {
 129                 dev_err(&pdev->dev, "error: adc_conditions not defined.\n");
 130                 return -EINVAL;
 131         }
 132         data->adc_conditions = pdata->adc_conditions;
 133
 134         /* Check the length of array and set num_conditions */
 135         for (i = 0; data->adc_conditions[i].state; i++)
 136                 ;
 137         data->num_conditions = i;
 138
 139         data->chan = iio_channel_get(&pdev->dev, pdata->consumer_channel);
 140         if (IS_ERR(data->chan))
 141                 return PTR_ERR(data->chan);
 142
 143         data->handling_delay = msecs_to_jiffies(pdata->handling_delay_ms);
 144
 145         INIT_DEFERRABLE_WORK(&data->handler, adc_jack_handler);
 146
 147         platform_set_drvdata(pdev, data);
 148
 149         err = devm_extcon_dev_register(&pdev->dev, data->edev);
 150         if (err)
 151                 return err;
 152
 153         data->irq = platform_get_irq(pdev, 0);
 154         if (!data->irq) {
 155                 dev_err(&pdev->dev, "platform_get_irq failed\n");
 156                 return -ENODEV;
 157         }
 158
 159         err = request_any_context_irq(data->irq, adc_jack_irq_thread,
 160                         pdata->irq_flags, pdata->name, data);
 161
 162         if (err < 0) {
 163                 dev_err(&pdev->dev, "error: irq %d\n", data->irq);
 164                 return err;
 165         }
 166
 167         return 0;
 168 }
 169
 170 static int adc_jack_remove(struct platform_device *pdev)
 171 {
 172         struct adc_jack_data *data = platform_get_drvdata(pdev);
 173
 174         free_irq(data->irq, data);
 175         cancel_work_sync(&data->handler.work);
 176
 177         return 0;
 178 }
 179
 180 static struct platform_driver adc_jack_driver = {
 181         .probe          = adc_jack_probe,
 182         .remove         = adc_jack_remove,
 183         .driver         = {
 184                 .name   = "adc-jack",
 185                 .owner  = THIS_MODULE,
 186         },
 187 };
 188
 189 module_platform_driver(adc_jack_driver);
 190
 191 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
 192 MODULE_DESCRIPTION("ADC Jack extcon driver");
 193 MODULE_LICENSE("GPL v2");